Thank you, Larry and Frank, for clearing up a great mystery! As I think
about it, the structure seems similar to the use of reverse form in tags:
"It's a nice day, isn't it?". This reversal is very hard for some second
language learners of English to master, esp. when the base sentence is
negative and the tag positive: "He didn't do it, did he?" which is
answered: "Yes" [=he didn't]. One of my Japanese students learned to add a
full sentence after every such affirmative, because he knew we'd be
confused otherwise. "So don't I" seems to be related also to the
rhetorical affirmative "Don't I though?" after something like "You look
very happy." I'm curious now about what follows a negative: "The Colts
don't want this one. So do the Pats [=not want it]. Not credible, of
course, but might this work?!

At 06:02 PM 3/14/98 -0500, you wrote:
Larry Horn said:

I haven't gone through all my messages, so I don't know if someone else=

responded to Beverly on this, but the answer is yes, "So don't I" =3D 'So=
do
I'. It's essentially New England, as Labov said, and not all of New
England. Someone from DARE probably knows the distribution, but it's at
least extant here in Connecticut and in Massachusetts. I've seen it in
novels (labelled as local to some part of New England) and in one memorab=
le
headline from the early 1970's in the Boston Globe:

THE COLTS WANT THIS ONE? SO DON'T THE PATS

As seen here, it always follows a positive and the negation is pleonastic=
=2E
Whether there's a different construction found after negatives I don't
know.

Larry

*************

And as a transplant to New England from the Midwest (I moved to N.E. in
1978), I can attest to having heard this use of the negative for jocular
effect, and being struck by it. I had not encountered it in all my years=